Further characterization of autoantibodies to GABAergic neurons in the central nervous system produced by a subset of children with autism

<p>Abstract</p> <p>Background</p> <p>Autism is a neurodevelopmental disorder characterized by impairments in social interaction and deficits in verbal and nonverbal communication, together with the presence of repetitive behaviors or a limited repertoire of activities and interests. The causes of autism are currently unclear. In a previous study, we determined that 21% of children with autism have plasma autoantibodies that are immunoreactive with a population of neurons in the cerebellum that appear to be Golgi cells, which are GABAergic interneurons.</p> <p>Methods</p> <p>We have extended this analysis by examining plasma immunoreactivity in the remainder of the brain. To determine cell specificity, double-labeling studies that included one of the calcium-binding proteins that are commonly colocalized in GABAergic neurons (calbindin, parvalbumin or calretinin) were also carried out to determine which GABAergic neurons are immunoreactive. Coronal sections through the rostrocaudal extent of the macaque monkey brain were reacted with plasma from each of seven individuals with autism who had previously demonstrated positive Golgi cell staining, as well as six negative controls. In addition, brain sections from adult male mice were similarly examined.</p> <p>Results</p> <p>In each case, specific staining was observed for neurons that had the morphological appearance of interneurons. By double-labeling sections with plasma and with antibodies directed against γ-aminobutyric acid (GABA), we determined that all autoantibody-positive neurons were GABAergic. However, not all GABAergic neurons were autoantibody-positive. Calbindin was colabeled in several of the autoantibody-labeled cells, while parvalbumin colabeling was less frequently observed. Autoantibody-positive cells rarely expressed calretinin. Sections from the mouse brain processed similarly to the primate sections also demonstrated immunoreactivity to interneurons distributed throughout the neocortex and many subcortical regions. Some cell populations stained in the primate (such as the Golgi neurons in the cerebellum) were not as robustly immunoreactive in the mouse brain.</p> <p>Conclusions</p> <p>These results suggest that the earlier report of autoantibody immunoreactivity to specific cells in the cerebellum extend to other regions of the brain. Further, these findings confirm the autoantibody-targeted cells to be a subpopulation of GABAergic interneurons. The potential impact of these autoantibodies on GABAergic disruption with respect to the etiology of autism is discussed herein.</p

Autoimmunity in a cohort of 471 patients with primary antibody deficiencies

<p><b>Objectives</b>: The aim of this study was to evaluate the frequency of autoimmunity in primary antibody deficiency (PAD).</p> <p><b>Methods</b>: A total of 471 patients with PADs enrolled in this retrospective cohort study. For all patients’ demographic information, clinical records and laboratory data were collected to investigate autoimmune complications.</p> <p><b>Results</b>: Autoimmune disorders as the first presentation of immunodeficiency were recorded in 11 patients (2.5%). History of autoimmunity was recorded in 125 patients during the course of the disease (26.5%). The frequency of autoimmunity in common variable immune deficiency (32.0%) was higher than other forms of PADs. The most common autoimmune manifestations were reported to be autoimmune gastrointestinal disease and autoimmune cytopenias. Among patients with autoimmunity, 87 patients (69.6%) had a history of one autoimmune disorder, while 38 patients (30.4%) had a history of multiple autoimmunities. The immune thrombocytopenic purpura and autoimmune hemolytic anemia were the most two concomitant autoimmune disorders in 16 (42.1%) of 38 patients with multiple autoimmunities. Comparing the frequency of Tregs in PAD patients with autoimmunity showed that, patients with multiple autoimmunities had lower Tregs than those with single autoimmunity (<i>p </i>= 0.017).</p> <p><b>Conclusion</b>: It is important that non-immunologist physicians be alert of the associated autoimmunity with PADs in order to reduce the diagnostic delay and establish timely immunoglobulin replacement therapy in these patients.</p